docs: def get_data(self):
          """
          :returns:
              an array of dtype perf_dt, with the information
              of the monitor (operation, time_sec, memory_mb, counts);
              the lenght of the array can be 0 (for counts=0) or 1 (otherwise).
          """
          data = []
          if self.counts:
              time_sec = self.duration
              memory_mb = self.mem / 1024. / 1024. if self.measuremem else 0
              data.append((self.operation, time_sec, memory_mb, self.counts))
          return numpy.array(data, perf_dt)